Cutting bit assemblies for such applications as mining or road milling typically comprise a cutting bit, sometimes referred to as a cutting pick or cutting tool, rotatably mounted within a support block. The support block is, in turn, mounted onto a drum or other body, typically by welding, which is, in turn, driven by a suitable drive means. When a number of such support blocks carrying cutting bits are mounted onto a drum, and the drum is driven, the cutting bits will engage and break up the material (e.g., earth strata) to be mined or removed. The general operation of such a mining machine or construction machine (e.g., a road planing machine) is well known in the art.
Heretofore, various retainers have been proposed or used to mount a cutting bit, rotatable or otherwise, within a support block.
As one example of such a retainer, U.S. Pat. No. 4,505,058 to Peterson shows a retainer having two legs. This retainer is to be used in conjunction with a support block having a recess with specially configured sidewalls that cooperate with the bends in the retainer legs to hold the retainer in place.
As another example, U.S. Pat. No. 4,883,129 to Lonn et al. shows another retainer that overlaps a cutting bit shank and a support block along substantially the entire length of the retainer. This retainer provides a single, continuous shear zone along its entire length.
As still another example, U.S. Pat. No. 6,428,110 to Ritchey et al. discloses a retainer used to retain a cutting bit in a holder. The retainer is stamped out of a piece of sheet steel and is received within an annular grove adjacent to the axial rearward end of the cutting bit. Although this retainer functions in a satisfactory fashion, certain drawbacks occur because the retainer is stamped from sheet steel.
One drawback connected with the stamped retainer of U.S. Pat. No. 6,428,110 is the presence of jagged portions along all or part of the peripheral edge of the retainer. This jagged portion can occur due to tearing or shearing of the material (e.g., steel) during the stamping process. The presence of the jagged portion results in a less than desirable surface finish for the retainer. It would thus be desirable to provide a retainer that presents a surface that does not have jagged portions along its peripheral edge, but instead, has a smooth surface finish along its peripheral edge.
Another drawback connected with the stamped retainer of U.S. Pat. No. 6,428,110 is the presence of so-called “fall off” on the exterior edge of the projections (or ears) that project in a radial outward direction from the retainer body. More specifically, this “fall off” exists when the exterior edge of the projection is not substantially perpendicular to the front or rear surface of the retainer, but instead, has an angled orientation with respect to such surfaces. It would be desirable to provide a retainer that presents projections (or ears) that do not exhibit this “fall off”, but instead, has projections that have an exterior edge that is generally perpendicular to the front and rear surfaces of the projection (or ear).
Still another drawback connected with the stamped retainer of U.S. Pat. No. 6,428,110 is the fact that the grain direction of the steel is dependent upon the direction in which the sheet steel is fed into the stamping press. The grain direction of the steel can run either parallel or perpendicular to the mouth opening of the retainer. It would thus be desirable to provide a retainer that has a consistent grain direction that runs in a direction that is generally parallel to the central longitudinal axis of the retainer body so that the grain direction in the retainer is consistent from part-to-part.